Abell, you're in the right place, Start > Run, type in "msconfig", (without the quotes), click OK then in the System Configuration Utility click the Startup tab.
This will tell you all the processes/programs set to start when you boot up your computer.
You then have 2 choices;
1] Find the programs that are running and check their Options or Preferences, and look for something like, "Start on startup", or "Place icon in System Tray", (the area next to your clock), and unset those options, or,
2] In the System Configuration Utility, click the General tab, choose "Selective startup", make sure all the options underneath are ticked, then return to the Startup tab and untick the programs you do not want to start on startup. It may be a process of elimination, or a "one by one" process, eg, untick one program, reboot, see if your PC works ok, then repeat for the next program.
If you use the Selective Startup option and click Apply, you will be prompted to restart your computer. Make sure all programs are closed down and click OK. When the PC restarts, you will get a warning message on your desktop reminding you that you have chosen selective startup. You can suppress this message within that reminder box, and you won't see it again until you change anything in the System Configuration Utility again.
You say that the source is in the registry and that is true, but there is nothing you can do about that. Windows runs from the registry and it is essential, and all programs installed on your computer have entries there. But by selecting to stop programs running at startup all you're doing is changing one value in registry for another.
Once you are happy with the way your PC works with the selective startup, you can return to the Startup tab of the SCU and click the "Cleanup" button. This may or may not remove entries from the startup tab. If a program has been removed completely from your computer, (uninstalled), the cleanup button removes any orphan entries from this tab. It may also remove entries even if the program is still installed, but it may not.
I have a Dell 386 system 600mh with 256k memory. I am running short of resources because of so many items running in the background. They are listed in the config startup folder. Apparently, because the source is in the registry, even if I delete them from this folder, when the system is restarted, the registry reinstalls these programs into the start folder. How should I go about removing those programs permanently from this config startup tab? Thanks for your help. I'm sure someone has the answer.